I have owned a couple Jayco travel trailers. Still have one for sale... We are shopping the Heartland toy haulers, and I have also shopped the Jayco toy haulers too.
I think the difference comes down to quality. I really like jayco. Especially their 2 year warranty. As much as these rigs cost, I think a 2 year warranty should be standard with Heartland too.
The fit/finish of the Cyclone seems visibly better than Jayco. The jayco I was in, had sloppy trim work (ie; poor angle cuts in trim work, etc). The power of the electric levelers are inferior to the hydraulic leveling in the cyclone. But the jayco doesn't weigh as much either.. Maybe it's a trade off. But I've read a lot about the electric leveling system not performing. They don't have the strength the hydraulic system does.
I think jayco may not charge as much for some of the options (party deck; 3 season garage wall;...)
That $10,000 difference also may not be as extreme as it appears. Are you talking MSRP difference, or actual sale/negotiated price?
In the end, for me- all things being fairly equal, I would look hard at the 2 year factory warranty.